1. Technical Field
The present invention relates to a pyroelectric light detector, a pyroelectric light detecting device, an electronic device and the like.
2. Background Technology
Thermal type light detectors are known as light sensors. Thermal type light detectors absorb light radiated from an object using a light absorption layer, convert the light to heat, and measure changes in temperature using a heat detecting element. As thermal type light detectors, for example, there are thermopiles that directly detect rises in temperature accompanying light absorption as thermoelectric power, pyroelectric elements for detecting electric polarity changes, bolomoters that detect rises in temperature as resistance changes and the like. The thermal type light detectors have a feature of having a broad band of wavelengths that can be detected.
With the pyroelectric light detector which is an example of a thermal type light detector, infrared light which is one example of light radiated from an object is absorbed and converted to heat by an infrared light absorption layer, for example. By giving that heat to a pyroelectric body, a change occurs in the pyroelectric body's spontaneous polarization volume. The infrared light volume is detected by pyroelectric current based on the change volume.
In recent years, using semiconductor manufacturing technology (MEMS technology or the like), attempts have been made at manufacturing more compact thermal type light detectors. In Unexamined Patent Publication H08-271344, noted is a monolithic heat sensitive sensor equipped with a pyroelectric layer. With this pyroelectric light detector, a pyroelectric light detecting element is formed using semiconductor manufacturing technology on an integrated circuit substrate. In FIG. 6 of Unexamined Patent Publication H08-271344, disclosed is a constitution for which two pyroelectric elements, constituted with a pyroelectric material thin film consisting of a dielectric sandwiched by electrodes, are connected by a common plate.
Also, in FIG. 2 of Unexamined Patent Publication 1405-187917, noted is an infrared sensor equipped with a pyroelectric film. With the sensor equipped with this pyroelectric film, a lower electrode, pyroelectric film, and upper electrode are formed in that order on an insulating film supported on the substrate, and a light absorbing film is formed on the upper electrode and the pyroelectric film.